Box wrench

ABSTRACT

This invention relates to a box wrench comprising an operational rod of which a center portion is formed into an angled portion and which is provided at its lower end with an expanded portion having a concave chamber with an inner opening at its bottom, a box having a hexagonal chamber at one side and a concave chamber at an other side; the rear end of said box being butted to the lower end of said expanded portion of said operational rod, a joint member being provided at both ends with spherical portions being to be inserted respectively in said concave chambers, a spring being inserted in said inner opening and fixed to the bottom thereof at its one end and to one of said spherical portions of said joint member at its other end.

United States Patent [19'] N akayama 1-Jan. 29, 1974' BOX WRENCH [76] Inventor: Eiji Nakayama, 1140,

Nishiyokkamachi, Sanjo, Japan [22] Filed: June 28, 1972 [21] Appl. No.: 266,896

[52] U.S. Cl 81/177 UJ, 81/121 R [51] Int. Cl B25b 13/00 [58] Field ofSearch 81/177 F, 177 PD, 177 UJ,

81/1778; 177.9, 121 R, 121 A, 121 B;

[56] I References Cited UNITED STATES PATENTS 1,392,220 9/1921 Quint 81/177 UJ X 386,547 7/1888 Martin 285/269 X Primary Examiner-James L. Jones, Jr. Assistant ExaminerJames G. Smith Attorney, Agent, or Firm-Ladas, Parry, Von Gehr, Goldsmith & Deschamps [5 7] ABSTRACT This invention relates to a box wrench comprising an operational rod of which a center portion is formed into an angled portion and which is provided at its lower end with an expanded portion having a concave chamber with an inner opening at its bottom, a box having a hexagonal chamber at one side and a concave chamber at an other side; the rear end of said box being butted. to the lower end of said expanded portion of said operational rod, a joint member being provided at both ends with spherical portions being to be inserted respectively in said concave chambers, a spring being inserted'in said inner opening and fixed to the bottom thereof at its one end and to one of said spherical portions of said joint member at its other end.

1 Claim, 4 Drawing Figures BOX WRENCH This invention relates to a box wrench, more particularly, a box wrench having a universal joint which has an improved form. It is the object of the present invention is to provide a box wrench of which a rotational operation is made smoothly and which is rotated always surely and has a large durability.

A box wrench with which the present invention is concerned comprises an operational rod provided with an angled portion at a center and with an expanded portion having a cavity, a box having a hexagonal cavity at one end and a concave chamber at an outer end; said both cavities being butted to each other, a joint member provided at both ends with terminal portions which are inserted in said both cavities, and a spring inserted in an inner opening bored at the bottom of said cavity of said expanded portion and fixed one end to the inner end of the opening and an other end to one of said terminal portions of said joint member.

.The invention will best be understood by reference to the following detailed description and claim taken in conjunction with the accompanying drawings in which:

FIG. 1 is a perspective view of the invention,

FIG. 2 is a sectional view taken along line 2-2 of FIG. 1,

FIG. 3 is an elevation view of a joint member of the wrench,

FIG. 4 is a plan view of the joint member.

Referring to the drawings, an operational rod 1, of which a center portion 2 is formed into an angled portion having a proper length, is provided with a head portion 3 in which is bored a lateral hole 4 to be inserted a lever (not shown) therein. The operational rod 1 is also provided with an expanded portion 5 at its lower end. The expanded portion 5 has a cavity 6 which has a square cross section in which terminal portion 13 of a later described joint member 12 is inserted. At the bottom of the cavity 6 is bored an inner opening 7 in which a spring 8 is to be inserted. The spring 8 is fixed to the bottom of the inner opening 7 at one end and to 7 one of the terminal portion 13 of the later described joint member 12 at the other end by suitable means. A box 9 has a hexagonal chamber 10 to be fitted to a nut or the like at one end and has a cavity 11 at the outer end. The square cross section in which the terminal portion 13 of the later described joint memeber 12 is inserted and therefore the same cross section with that of the cavity 6 of the expanded portion 5 of the operational rod 1. The side surface of the concave chamber 11 of the box 9 is butted to the side surface of the expanded portion 5 of the operational rod 1. A joint member 12, which is to be inserted in the both cavities 6 and 11 of the expanded portion 5 and the box 9, is provided with terminal portions 13 and 13 at both ends.

Each terminal portion l3'of the joint member 12 has four arcuate surfaces 14 and four spherical surfaces 14 which have the same center of curvature and of which the radius of curvature is smaller than that of the four arcuate surfaces 14. Thereby, the terminal portion 13 has a nearly square cross section and the largest width of the cross section thereof is nearly equal to the width of the square cavity 6 or 11. Projections 15 and 15 are attached respectively to the inner walls of the cavities 6 and 11, for instance, by welding after the terminal portions 13 and 13 have been inserted in the cavities 6 and 11. The projection 15 of the cavity 11 of the box- 9 receives only the pulling force exerted to the joint member 12 by the spring 8, both ends of which are firmly fixed to the joint member 12 and the bottom of the opening 7 of the operational rod 1 and prevents the terminal portion 13 from being removed from the cavity 11. The terminal portion 13 in the cavity 11 is pulled toward and engaged with the projection 15 of the cavity 11 by the spring 8. Thereby, the box 9 is pulled toward the operational rod 1 and the open end of the cavity 11 of the box 9 is fitted and engaged with the open end of the cavity 6 of the operational rod 1. Thus, the box 9 is held in alignment with the operational rod 1 under normal conditions as shown in FIG. 2.

In operation, a rotational force or torque imparted to the operational rod 1 is transmitted to the box 9 through the joint member 12 by the inner walls of the square cavities 6 and 11 and the arcuate surfaces 14 of the terminal portions 13. When treating the nut or the like located inclinedly against an operational direction, the top end of the expanded portion 5 of the operational rod 1 is separated from the rear end of the box 9 and the operational rod 1 is inclined against the axis of the box 9 as shown in FIG. 2 by the arcuate surfaces 14 and the spherical surfaces 14 of the terminal portion 13 of the joint member 12. In this fashion, the rota' tional force of the operational rod 1 is transmitted to the box 9 through the joint member 12.

According to the invention, the wrench comprises an operational rod 1 of which a center portion is formed into an angled portion 2 and which is provided at its lower end with an expanded portion 5 having a cavity 6 with an inner opening 7 at its bottom, a box 9 having a hexagonal chamber 10 at one end and a cavity 11 at an other end; the rear end of said box 9 being butted to the lower end of said expanded portion 5 of said operational rod 1, a joint member 12 being provided at both ends with terminal portions 13 and 13 being to be inserted respectively in said both cavities 6 and 11, and a spring 8 being inserted in said inner opening 7 and being fixed to the bottom thereof at one end and to one of said terminal portions 13 of said joint member 12 at an other end. As there is supported the joint member, which joins the box to the operational rod universally, by the spring inserted in the inner opening of the operational rod, there is strongly exerted a pulling operation to the joint member, and the box and the operational rod are kept always in a regular jointed-state thereby. As the joint members are always closed tightly as a result of the strong pulling operation of the spring, dusts never break into the cavities and therefore the wrench may have a large durability as a whole. Moreover, even when the wrench is used in an inclined fashion, the wrench never wobbles and is steadily operated rotationally as the joint member is held firmly.

What is claimed is: I

l. A box wrench comprising an operational rod having a square cross sectioned cavity at one end and a small opening bored at the bottom of said cavity, a box having a socket to be engaged over a nut or the'like at one end and a square cross sectioned cavity at the other end; the open ends of said both cavities facing each other, a joint member being provided at both its ends with terminal portions respectively having four arcuate surfaces and four spherical surfaces and being inserted in said cavities, a spring being inserted in said opening and fixed to the bottom thereof at one of its ends and to one of the terminal portions of said joint member at its other end. 

1. A box wrench comprising an operational rod having a square cross sectioned cavity at one end and a small opening bored at the bottom of said cavity, a box having a socket to be engaged over a nut or the like at one end and a square cross sectioned cavity at the other end; the open ends of said both cavities facing each other, a joint member being provided at both its ends with terminal portions respectively having four arcuate surfaceS and four spherical surfaces and being inserted in said cavities, a spring being inserted in said opening and fixed to the bottom thereof at one of its ends and to one of the terminal portions of said joint member at its other end. 